Facebook and other social media can help you be insulated to other opinions, cultures, and ways of thinking.
I am no expert, but my thoughts are that people are less left/right or republican/democrat in real life than many people are on Facebook. Almost everyone is socially liberal and fiscally conservative when polled without labels. The paradox is that when people are asked to fund more programs for education or the poor, they vote yes. When asked to vote to raise taxes, they always vote no.
But jobs are important to people in every election. People were excited about free college education, and thus Sanders campaign, as a form of retraining for the 75% without degrees in dead end jobs, but less excited about a higher tax burden, whether for healthcare or other programs. The perception is that the status quo isn’t interested in helping. And so “change” is voted in, whether Obama or Trump.
It’s not always about race or gender politics, and making it so drives people underground afraid to say why they actually supported Trump. There’s a big group of voters, call them the “undereducated”, or “poor”, that are black, white, hispanic, male and female, that vote almost exactly alike, and have the same attitudes towards politics and politicians, aligned almost exactly. That gets forgotten in analyzing how voters think (as everyone is fast to draw along racial or gender lines) and how polling got this so wrong.
Often “identity politics”, that is, aligning with a label, whether by gender, race, or political party, is a shorthand to keep from actually thinking about the actual policies, which are more important than the labels.
The media often seems to confuse the issue, as they like controversy, and like to apply labels and use that same shorthand thinking. Calling people names doesn’t seem to be a good approach during any season.